Moving the confirmation time slider in coin control to "fast" causes the priority to decrease #5552

When using coin control, moving the confirmation time slider to "fast" progressively causes the priority to go to "lowest". When the slider is at "normal", the priority is "medium".

Steps to reproduce: 0. enable coin control features in the options window

1. go to the send tab
2. click the "inputs..." button and select one or more medium priority inputs
3. click "choose" to expand the transaction fee portion
4. move the confirmation time slider to the right. as the the slider gets closer to the right, the priority will decrease.

Thats expected, but I also thought that this will probably confuse people. The thing is that the priority calucation is based on the slider, because in order to get a fast free-transaction, you need a higher priority than to get a normal-fast-free-transaction. And the priority label getting red means "You cant get a free transaction for the confirmation target you selected with the slider".

But maybe we should change this. So that the priority calucation is always based on confirmation target of 25 (as if slider=normal). But the label becoming red could be based on the target, so that you still know from the color, whether or not a free transaction is possible.